ISO: Butter frosting

I used to get this cake from a lady for special occasions but have moved and wish I could figure out how she made it.

She told me that the cake itself was a Betty Crocker White cake mix.  But the frosting is what was good.  She would store the cake in the freezer because room temperature would cause the frosting to get really soft (similiar to if you let butter sit out for a period of time).  She did tell me that she made the frosing primarily out of butter using a roux mixture.  I never quite understood what she meant but has anyone heard of this type of frosting?

Thanks!

Reviews and Replies:
1	ISO: Butter frosting
	Derek of Roscoe

2	Recipe(tried): Custard Frosting (cooked frosting with flour, milk, and butter) - Here's one that sounds close, Derek
	Micha in AZ

3	Recipe(tried): Favorte Frosting and Grandma Agnes' Jello Icing (cooked frosting with milk, flour, and butter/shortening)
	Micha in AZ

4	Thank You: Thanks for those recipes!
	Derek of Roscoe

5	Recipe(tried): My Aunt 'Moe' - our family cake lady frosting recipe....
	Heather Ketchel - Clawson, MI

6	Thank You: Custard Frosting - Thank you so much
	Barb = Parma, OH

7	Recipe(tried): Mom's Fluff Icing - Similar
	LEE - ASTON, PA

8	Lee, thanks for the yummy sounding post!
	Micha in AZ

9	Thank You: Frosting recipes - Thanks
	Derek of Roscoe